Screw device



Sept- 1942- STAPELFELDT 2,297,437

SCREW DEVICE Filed D90. 15, 1959 //7 van 20/1' Ame/d Sfapelfeldf Patented Sept. 29, 1942 scasw lmvrcn Arnold Stapelleldt, Berlin, Germany: vested in the Alien Property Custodian Application December 15, 1939, Serial No. 309,343 In Germany December 27, 1938 3 Claims.

This invention relates to high frequency iron core devices, specifically of the type which is adapted to be adjustingly screwed into a supporting member carrying the windings of the cooperating inductance coil.

Devices of the above-mentioned kind have been proposed in which the supporting member carries an internal thread and the high frequency iron core is provided with an external thread adapted to be adjustingly screwed into the former thread. This arrangement encounters the disadvantage that the thread on the high frequency core is easily subjected to fractures due to the brittleness of the material which unavoidably requires the thread to be designed with a considerable pitch on account of the impracticability of cutting a fine gauge thread. It is thus almost impossible to obtain an axial fine-adjustment of the core within the surrounding inductance coil.

My invention consists in certain featuresof novelty which will be fully understood from the following description and be pointed out in the appended claims, reference being had to the accompanying drawing, in which Figs. 1. mend it show a high frequency core according to the present invention, Fig. 1 being a side elevation, Fig. 10. being a cross sectional view through Fig. i and Fig. lb being an'end elevation;

Figs. 2 and 2a illustrate the same core after flexible material has been attached thereto, Fig.

- 2 being a side elevation and Fig. 2a being a cross section taken through the elevation of Fig. 2; and

Figs. 3 and 3a show the attachment of the core within a supporting member, Fig. 3 being a side elevation partially in section and Fig. 3a being an end view.

It is the object of this invention to provide a high frequency iron core device in which merely the member supporting the inductance coil is furnished with a thread, while the iron core itself carries a flexible material which is adapted to engage the thread of the supporting member. This expedient involves the beneficial advantage that the internal thread of the supporting member may be cut with the smallest desirable pitch,

thus allowing a very accurate fine-adjustment.

porting member.

This omission of a screw-thread on the high frequency iron core substantially strengthens its stability and rigidity and considerably reduces the hazard to damage.

With reference to the attached drawing, reference numeral 1 designates a high frequency iron core. This core is provided with a number of longitudinal slots or grooves 2 which are adapted to receive straps 3 of any suitable soft and flexible material, such as felt. These strips are fixed, preferably gummed in these grooves or slots as shown in Fig. 2 and project beyond the peripheral surface of the iron core so as to snugly engage a screw-thread which is cut in the inner surface of the supporting member carrying the cooperative inductance coil.

As a matter of convenience the upper or outer end of the high frequency iron core may be provided with a square-shaped projection as indicated at I or, alternatively a square-shaped recess 4 adapted to fit a wrench or other suitable tool for screwingly adjusting the iron core relative to the inductance .0011, when fine-adjustment of this inductance is required.

What is claimed is: I

1. An adjustable core arrangement comprising a tubular member having internal threads, a cylindrical high frequency iron core having a plurality of longitudinal grooves provided in its peripheral surface, and a strap of flexible material fixedly fastened in each of said grooves, said strap projecting beyond the peripheral surface of said core and being in engagement with said threads whereby said core may be screwingly adjusted axially alongsaid tubular member.

2. An adjustable core arrangement according to claim 1, characterized in that one end of the said high frequency iron core is provided with a square-shaped projection adapted to flt a tool for rotating the said iron core within the said supporting member.

3. An adjustable core arrangement according to claim 1, characterised in that one end of the said high frequency iron core is provided with a square-shaped recess adapted to fit a tool for rotating the said iron core within the said sup- ARNOLD BTW. 

